BIOL 527 Lecture Notes - Lecture 10: The Strongest, Gracilis Muscle, Posterior Column
1 Aug 2020
School
Department
Course
Professor
Document Summary
Moves affected portions of body away from a source of stimulation. The strongest withdrawal is from a painful stimulus . Pain receptors are stimulated> sensory neuron activated. Synapse on interneurons> stimulate motor neurons that innervate flexor muscles of the leg, thigh, foot, etc. When specific muscle contracts, opposing muscles must relax to permit the movement. This should lead to contraction of the extensor because of golgi tendon organ muscle spindles. But this would be counterproductive so interneurons prevent such competition through reciprocal inhlbition (i. e. antagonists are inhibited simultaneously. Stretch, tendon, and withdrawal reflexes are ipsilateral reflex arcs (stimulus & response occur on same side). Complements the flexor reflex and the 2 occur simultaneously. Step on tack, flexor reflex pulls foot away, crossed extensor stilfens other leg to support weigbt of the body. Several reflexes cooperate: integration and control or spinal refines. Infants toes curl up because descending motor pathways are not yet fully developed.
